Field of the Invention
The present invention relates to an adapter for a centrifuge tube and to a removal tool for removing the adapter from the centrifuge tube.
Description of the Prior Art
A centrifuge rotor is a device used with a centrifuge instrument in order to subject a sample of a liquid to a centrifugal force field. The sample is carried in a suitable container, such as a test tube. The sample container is itself received within a recess provided in the body of the centrifuge rotor. The axis of the recess may be parallel to or inclined with respect to the axis of rotation of the rotor. The rotor in the latter case is known as a fixed angle rotor.
The sample container may, in some cases, exhibit a physical size that differs from the physical dimension of the recess in the centrifuge rotor in which it is received. In these instances the sample container is introduced into the recess using an intermediate device called an adapter. The adapter is externally dimensioned and configured in a manner that makes it compatible for receipt within the recess in the centrifuge rotor and is internally dimensioned and configured to accept the sample container. The adapter with the sample container received therein are thus receivable as a unit within the recess of the rotor and the sample may be thus exposed to the centrifugal force field upon rotation of the rotor.
Relative centrifugal force (RCF) is a measure of the magnitude of the centrifugal force to which a sample is subjected during a centrifugation run. RCF is dependent upon the radial distance of the sample from the axis of rotation of the centrifuge rotor. In instances when an adapter is utilized the sample container is usually not located within the recess at the greatest radial distance from the axis of rotation. For example, if it is desired to separate in a fixed angle rotor the contents of a liquid sample carried in a microtube using a centrifuge rotor having recesses which are sized to accomodate a standard test tube an adapter must be used. Currently available adapters able to accommodate a microtube are physically configured to substantially duplicate the exterior dimensions of the standard test tube. An opening is provided in the adapter that conforms in shape and length to the microtube. This opening is typically formed in the adapter adjacent the upper end thereof. Thus, when the microtube is received within the adapter and the adapter inserted into the sample receiving recess the sample is disposed at a distance from the axis of the rotation of the rotor that is less than the radial distance between the axis of rotation and the bottom of the sample receiving recess in the fixed angle rotor. As a result the sample is exposed to a lesser relative centrifugal force during a run of a given duration. Typical examples of such adapters of this type are those manufactured and sold by the Medical Products Department of E. I. du Pont de Nemours and Company, Inc. as model numbers P/N 00410, 00425, 00419 and 00381.
At the termination of a centrifugation run the sample container must be removed from the sample carrying recess. Care must be exercised in order to avoid remixing the separated constituents or components of the sample. The degree of care which must be exercised when removing the sample is increased when an adapter has been used to carry the sample container.
In view of the foregoing it is believed advantageous to provide an adapter which will permit a sample container to be disposed at the maximum radial distance within a recess in a given centrifuge rotor and at the same time be extractable from the recess without remixing the separated components in the sample.